Neonatal jaundice, a yellowing of the skin as a result of hyperbilirubinemia, is an almost ubiquitous condition in newborn infants. In very rare circumstances, if an infant with signficant hyperbilirubinemia is undetected, kernicterus, a devastating and permanent neurologic condition, can develop. Still rare, but much more frequently, a neonate with significant jaundiced is not identified until the bilirubin level is ver high, necessitating complicated and expensive care to prevent bilirubin encephalopathy. Thus, the identification of infants with moderate hyperbilirubinemia, at levels that are easily treatable is a central focus of neonatal care in the US. Unfortunately, bilirubin levels typically peak in neonates around 96 hours of life, well after most infants are discharged from the newborn nursery. There is currently a lack of accurate, inexpensive and widely available methodologies to screen discharged infants for jaundice, leaving a notable void in the overall system of care designed to prevent severe hyperbilirubinemia. Our group of academic pediatricians and computer science and electrical engineering faculty has developed a non-invasive technology to measure bilirubin in newborn infants. The technology is based on the analysis of digital images of newborn skin that are obtained with a smartphone app that we have developed. A color calibration card is placed on the newborn's skin to control for different lighting, and other aspects of the image are standardized. The images are sent electronically to a central computer server for an analysis. The calculated bilirubin level is then downloaded to the smartphone app. In preliminary studies on a small number of infants, our technology, called the Bilicam app system, has accurately predicted bilirubin levels. The proposed study is designed to rigorously assess the ability of the Bilicam app system to accurately predict serum bilirubin levels in a racially, ethnically and geographically diverse sample of 250 newborn infants who are 3-5 days old, when bilirubin levels are peaking. The accuracy of the Bilicam app system in predicting serum bilirubin levels will be compared to published data on the accuracy of transcutaneous bilirubin meters, another non-invasive methodology for assessing newborn jaundice that is in widespread clinical use. The final goal of the project is to assess and improve the user experience with the smartphone app. A 2-year study period is planned.